【Java-API工具类】Base64Util类
756665228 发布于2017-12-29 14:46 浏览:7665 回复:4
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Base64Utilhttps://ai.baidu.com/file/658A35ABAB2D404FBF903F64D47C1F72

  • Base64Util工具类
package com.baidu.ai.aip.utils;

/**
 * Base64 工具类
 */
public class Base64Util {
    private static final char last2byte = (char) Integer.parseInt("00000011", 2);
    private static final char last4byte = (char) Integer.parseInt("00001111", 2);
    private static final char last6byte = (char) Integer.parseInt("00111111", 2);
    private static final char lead6byte = (char) Integer.parseInt("11111100", 2);
    private static final char lead4byte = (char) Integer.parseInt("11110000", 2);
    private static final char lead2byte = (char) Integer.parseInt("11000000", 2);
    private static final char[] encodeTable = new char[]{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};

    public Base64Util() {
    }

    public static String encode(byte[] from) {
        StringBuilder to = new StringBuilder((int) ((double) from.length * 1.34D) + 3);
        int num = 0;
        char currentByte = 0;

        int i;
        for (i = 0; i < from.length; ++i) {
            for (num %= 8; num < 8; num += 6) {
                switch (num) {
                    case 0:
                        currentByte = (char) (from[i] & lead6byte);
                        currentByte = (char) (currentByte >>> 2);
                    case 1:
                    case 3:
                    case 5:
                    default:
                        break;
                    case 2:
                        currentByte = (char) (from[i] & last6byte);
                        break;
                    case 4:
                        currentByte = (char) (from[i] & last4byte);
                        currentByte = (char) (currentByte << 2);
                        if (i + 1 < from.length) {
                            currentByte = (char) (currentByte | (from[i + 1] & lead2byte) >>> 6);
                        }
                        break;
                    case 6:
                        currentByte = (char) (from[i] & last2byte);
                        currentByte = (char) (currentByte << 4);
                        if (i + 1 < from.length) {
                            currentByte = (char) (currentByte | (from[i + 1] & lead4byte) >>> 4);
                        }
                }

                to.append(encodeTable[currentByte]);
            }
        }

        if (to.length() % 4 != 0) {
            for (i = 4 - to.length() % 4; i > 0; --i) {
                to.append("=");
            }
        }

        return to.toString();
    }
}
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共4条回复 最后由xiaojuelina回复于2021-01-11 04:36
#4∫の大觉寺回复于2020-09-23 15:57:52

这是自己写的加密工具吗?那解密呢?

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#3胖子哥0_0回复于2018-06-04 17:30:52

知道了,是jdk1.8的StringBuilder问题。

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#2胖子哥0_0回复于2018-06-04 16:26:13

File file = new File("E:/0754.jpg");
System.out.println(file.isFile() +"==="+ file.exists());
byte[] bytes1 = FileUtil.readFileByBytes("E:/0754.jpg");
System.out.println(bytes1.length);
String image1 = Base64Util.encode(bytes1);

楼主,我用这个工具类,文件是存在的,不过有些图片进行base64编码之后什么都没返回。在代码

case 0:
currentByte = (char) (from[i] & lead6byte);
currentByte = (char) (currentByte >>> 2);

这里  currentByte 是个?号,然后就跳出循环了。是对图片有什么要求吗?

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